Structural analysis of a surfboard

INTRODUCTION

In recent years new technologies have enhanced the world of sports through the use of hydro-aero dynamics and structural simulation. Looking at professional sailors piloting foiling sailing boats, like Americas Cup or F1 cars taking speeds over 300km/h are just a few examples.

We believe that through innovation everything is possible and that this type of technology implementation should be present at all professional competitive sport.  This is why, we introduce you this initial approach to the structural analysis of a surf board.

GOAL

The aim of this project was to simulate and examine the various stresses and loads which a surfboard experiences in a typical session.

Surfboards have always been designed through user and shaper experience and prototyping.

The addition of simulation to the design spiral could result in a considerable number of positive impacts, like for example the improvement in performance or reduction in prototyping costs.

ANALYSIS DEVELOPMENT

Choice of surfboard

A traditional construction surfboard was selected for this initial project. The selected table had the following characteristics:

  • dimensions 6’0 x 19 x 23/8 ft
  • constructed with foam of density 30 km/m³, wood stringer and fibreglass.

Analysis

The board was modelled in 3D and into FEA (finite elements analysis) software. We analysed the board’s flexion and torsion.

Flexion, colloquially known as “flex” within the surfing community, is the amount the board bends from nose tip to the tail. The flex of a board is what gives a board its lively feel and responsiveness.

In the following images we can see the linear static analysis in flexion with different results.

The torsion is the amount a board may twist from the center to the side-rails. Torsion is also related to the responsiveness of the board, normally it gives a smoother and more forgiving ride but to an excess might result in a feeling of ‘softness’ and a lack of response. In big terms this measurements come related to its rigidity.

In the following images we can see the linear static analysis in torsion with different results.

Conclusions

These two tests are just an example of the evaluations that may be carried out on a surfboard. Vibration testing could be an equally interesting field for further investigation.

Nowadays, surfboard design and manufacture has developed extensively and there are many more available options apart from the traditional wood centre stringer boards, such as parabolic stringers in wood, multi-density foam and carbon tape. Tools like FEA allow us to evaluate new manufacturing techniques and refine and improve upon current ones.

As previously said, introducing simulations into the design spiral would have a positive impact on product innovation, reducing prototyping and manufacturing costs and shortening time to market. In addition to providing both manufacturers and sellers with sales arguments based on real numbers, even being able to personalize the tables according to the type of client or surfing area.